1. Field of the Invention
This invention relates to a heated glass sheet press bending station and also relates to a method for job switching.
2. Background Art
Glass sheet processing systems have previously included press bending stations that are located downstream from a heating furnace to provide press bending of the heated glass sheets after heating thereof to bending temperature within the furnace. The U.S. Pat. Nos. 5,368,625 Mizusugi and 5,545,245 Mizusugi disclose a glass sheet processing system having a press bending station that is located downstream from a roll bending station that is also located downstream from the associated heating furnace. These Mizusugi patents have the roll bending stations provided with horizontal rolls and laterally spaced sets of inclined rolls with the rolls of each inclined set having progressively increasing inclination along the direction of conveyance to form each heated glass sheet and to provide conveyance thereof to the press station where the glass sheet is subsequently press bent between lower and upper molds.
Roll bending of heated glass sheets has also been performed as disclosed by French Patent 2221409 of inventor Maurice Nedelec which has conveyor rolls that are supported and rotatively driven outside of a furnace heating chamber to receive a heated glass sheet prior to simultaneous tilting of the rolls to form the heated glass sheet within the heated chamber.
Upon switching from one glass sheet production job to another, the changeover time represents lost production which necessarily increases the cost of the resultant product and it is thus advantageous for such job switching to be performed as quickly as possible.
One object of the present invention is to provide an improved press bending station for press bending heated glass sheets.
In carrying out the above object, the press bending station constructed in accordance with the present invention to press bend heated glass sheets includes a lower wheel bed for receiving a heated glass sheet to be press bent. The lower wheel bed includes a support and a plurality of wheel assemblies. Each wheel assembly includes a housing having an upper end including a wheel and also having a lower end including a detachable connection for detachably connecting the wheel assembly to the support. A drive mechanism of the press bending station provides rotational driving of the wheel of each wheel assembly upon connection thereof to the support. A lower mount of the press bending station provides support for a lower press ring having a curved shape facing upwardly and being received within the wheel bed below the wheels of the wheel assemblies in a ring shape thereof where no wheel assemblies are located. An upper mount of the press bending station supports an upper press mold having a downwardly facing curved forming face complementary to the upwardly curved shape of the lower press ring. An actuator of the press bending station provides relative vertical movement between the wheel bed and the lower press ring and between the lower press ring and the upper press mold to move the heated glass sheet above the wheel bed and into pressing engagement between the lower press ring and the upper press mold to press bend the glass sheet.
In one embodiment of the press bending station, the wheel bed has a curved shape transverse to a direction of conveyance along which the wheel bed receives the heated glass sheet which has a prebent curved shape transverse to the direction of conveyance. This embodiment of the press bending station has the support of the wheel bed constructed to include a plurality of rails that extend along the direction of conveyance and have different elevations along a direction transverse to the direction of conveyance to provide the curved shape of the wheel bed.
In another embodiment, the wheel bed has a flat shape along and transverse to the direction of conveyance along which the wheel bed receives the heated glass sheet. This embodiment has the wheel bed constructed to include a plurality of rails that extend along the direction of conveyance and have the same elevation along a direction transverse to the direction of conveyance to provide the flat shape of the wheel bed.
Each of the embodiments of the press bending station has the drive mechanism constructed to include a continuous drive member on each rail for rotatively driving the wheels of the wheel assembly attached to the rails. Each wheel assembly includes a lower drive member rotatably supported on the housing and rotatively driven by the continuous drive member of the associated rail to rotatively drive the wheel of the upper end of the housing. Each wheel assembly includes a drive belt that extends between the lower drive member and the upper wheel of the upper end of the housing to provide the rotary driving of the wheel.
The detachable connection of each wheel assembly includes a clamp that provides the detachable connection thereof to the support.
Another object of the present invention is to provide an improved method for glass sheet press bending job switching.
In carrying out the immediately preceding object, the job switching method of the invention is performed by removing a first lower press ring with a first upwardly facing curved shape within a first ring shaped void in a lower wheel bed having wheel assemblies that have detachable connections to a wheel bed support that provides rotational driving of wheels of the wheel assemblies connected to the support. Any wheel assemblies necessary to provide a second ring shaped void are detached from the wheel bed support so as to receive a second lower press ring with a second upwardly facing curved shape, and any necessary wheel assemblies that are not in the second ring shaped void are attached in the first ring shaped void. A second lower press ring with an upwardly facing curved shape is installed within the second ring shaped void in the lower wheel bed to thereby permit bending of different shapes.
In performing the glass sheet press bending job switching method, some jobs require that a first upper press mold having a downwardly facing curved shape complementary to the first upwardly facing curved shape of the first lower press ring is removed from an upper mount above the wheel bed. Furthermore, a second upper press mold having a downwardly facing curved shape complementary to the second upwardly facing curved shape of the second lower ring mold is installed to complete the job switching in such applications.
The objects, features and advantages of the present invention are readily apparent from the following detailed description of the preferred embodiments when taken in connection with the accompanying drawings.